entirely pertinent to science to undertake to search for the hidden traces of man's former history, if there be any. It is no dreamland or cloudland which it proposes to explore. It is no Quixotic adventure which it has gotten up to astonish and alarm the vulgar. If our human ancestors have lived fifty or one hundred thousand years longer on this planet than was generally supposed, it is quite likely they have left some traces behind them. And if so, it is perfectly legitimate for science to gather, collate, and interpret those traces. And from what we know of her past achievements, we may assure ourselves that if man has had such a pre-historic existence, science will most undoubtedly prove it. She has proved beyond all sane contradiction the great age of the earth. She has proved in like manner the vast extent of the universe in space. She has proved the existence of manifold forms of animal life on this planet for countless ages before the incoming of man, according to the popular chronology. She has proved, approximately, the order and succession of animal life as it arose, and the forms it assumed as the long cycles of ages rolled on. All these were legitimate themes for science; and all of them were opposed to the popular belief at the time—as much so as is the antiquity of man now. And further, we say that the mere suspicion that any such thing may be—the mere surmise of any such fact—the merest inkling which scientific men may get of a secret yet hidden beneath the veil, and waiting to be revealed—is a sufficient justification of those tentative efforts of science which often result in the attainment of some grand discovery. Let no timid religionist charge upon scientific men that they are conspiring with malice prepense to undermine the popular creeds and overthrow the Bible. This is sheer nonsense. They follow where nature beckons them. If man has had a high antiquity on this earth, science will find it out and prove it beyond a doubt. If he has not had such antiquity, science will discover that too, and prove it. All we have to do is to let science have her way.

Another remark which we make here, is respecting the power which a single fact may have in this investigation. It is not often that great questions in history, or social polity, or jurisprudence are determined by a single fact. The great results of history, economics, and law are effected by the converging power of many facts. So also in science. Its great results are determined by the accumulated power of multitudinous facts. Its final categories are fixed by abundant certainties and manifold inductions. And yet it may sometimes occur that a single fact may be of such a nature that there is no escaping the conclusion which it forces upon the mind. It may concentrate in itself all the elements of certainty usually obtained from many sources. It may be determinative in its very nature, and admit of scepticism only at the expense of rationality. A single human grave, with its entombed skeleton, discovered in some uninhabited waste, where it was never known the foot of man had trod, would prove conclusively that human footsteps had once trod there. The discovery of a single weapon of the quality and temper of the Damascus blade amid the ruins of a buried city, would prove as fully as would the discovery of a thousand that the people of that age of the world understood the methods of working steel. One canoe found moored to the bank of the Delaware, the Schuylkill, or the Susquehanna, when the white man began to penetrate this continent, would have been sufficient to prove that the aborigines understood, to that extent, the art of navigation. So in science, one fossil of a different species from any found heretofore in a certain deposit is sufficient to add another to the forms of life represented by that deposit. One fossil found lower in the geological scale than life was supposed to have begun on this planet, is sufficient to prove that it had a still earlier beginning. So with regard to contemporary forms of life, one fact may be sufficient to warrant or compel a conclusion. Hugh Miller cites the instance of fossil dung being found as proving to the anti-geologists that these fossils were once real living creatures, and not mere freaks of nature. The instance might not be thought conclusive, for if the Author of nature saw fit to amuse himself by making the semblances of huge iguanodons, elephants, and hippopotami, in the solid rocks, it might readily be supposed that He would extend His amusement to the making of fossil dung.[2] But now, if in the fossil entrails of the cave hyena the bones of a hare should be found, it would prove conclusively to any but an anti-geologist, that the hare lived contemporaneously with the hyena.

These remarks are not thrown in by way of apology for the paucity of facts adduced by Sir Charles Lyell to prove the antiquity of man, but merely to illustrate the force which it is possible, in certain circumstances, for a single fact to have. Thus, for instance, the Scotch fir is not now, nor ever has been in historic times, a native of the Danish isles, yet it has been indigenous there in the human period, for Steenstrup has taken out with his own hands a flint implement from beneath one the buried trunks of that species in the Danish peat bogs. Again, if an implement of human workmanship is found in close proximity to the leg of a bear, or the horn of a reindeer, of extinct species, in an ancient cavern, and all covered by a floor of stalagmite, we see not how the conclusion is to be avoided that they were introduced into the cave before the stalagmite was formed; and in that case the inference that they were contemporaneous, or nearly so, may well be left to take care of itself. The attempt has been made to treat with levity the whole subject of the antiquity of man because of the numerical meagreness of the facts adduced in support of it. But as to this, it need only be observed that as a new theme for investigation, its facts must necessarily be meagre, as must be the facts of any science in its inchoate condition, and that they are steadily growing in volume, so that it is not safe to venture a final verdict against it on that score. The facts in support of the globular form of the earth, or the Copernican theory of the heavens, or the great age of the earth, were at one time meagre—they are not so now. Sir Charles Lyell is a pioneer explorer in a new and mysterious realm: the time may come when, amid the abundance of the treasure gathered from it, the scanty hoard which he opens to his reader may seem meagre enough.

Nevertheless, Sir Charles Lyell is fully a believer in the doctrine of the high antiquity of man. His book is not merely a debating-club discussion of the pros and cons, the probabilities for and against the doctrine, but rather the earnest pleading of the advocate fully persuaded that the truth is on his side. Not that it displays any forensic heat;—it is calm, cautious, dispassionate; but it has the air of one governed by conviction, and he often assumes the entire truth of his conclusions with the quiet nonchalance of a man seemingly unconscious that what he regards as matters of established certainty will be viewed by the great majority of his fellow beings as startling novelties.

The main stream of the geological evidence of the antiquity of man tends to one point, viz., that man coexisted with the extinct animals. There are collateral branches of proof, but this is the main channel. The remains of man and of man's works and the remains of extinct races of animals lie side by side, and claim from the geologist the same meed of antiquity. This is the burden of the book before us. We offer the reader a brief outline of this evidence. In doing so, we